Resp 3 Flashcards

1
Q

Outward forces (mmHg)

A

Capillary 7;
Interstitial osmotic pressure 14;
Negative interstitial fluid pressure 8;
Total 29

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2
Q

Inward forces (mmHg)

A

Plasma protein osmotic pressure 28

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3
Q

Elevated PO2 levels are associated with

A

Increased O2 levels in the inhaled air;

Polycythemia

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4
Q

Decreased PO2 levels are associated with

A
Decreased O2 levels in air;
Anemia;
Heart decompensation;
COPD;
Restrictive pulm dz;
Hypoventilation
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5
Q

The amount of gas dissolved in a solution is proportional to its partial pressure

A

Henry’s Law

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6
Q

Equation for dissolved oxygen in blood

A

PaO2 x 0.003

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7
Q

Diffusion of a gas is directly proportional to:

A

Pressure gradient, membrane area, & gas solubility

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8
Q

Diffusion of a gas is inversely proportional to:

A

Membrane thickness and square root of molecular weight

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9
Q

A-a gradient

A

PAO2 - PaO2. Difference b/w alveolar PO2 and arterial PO2

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10
Q

A-a gradient normal range for PO2 & PCO2

A

5-15 mmHg;

2-10 mmHg

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11
Q

Alveolar gas equation (calculates PAO2)

A
PAO2= PIO2 - PACO2/R
R = resp quotient (0.8)
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12
Q

Hypoxemia d/t V/Q mismatch, diffusion block, or right-to-left shunt would effect A-a gradient how?

A

Increased

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13
Q

Hypoxemia d/t hypoventilation effects A-a gradient how?

A

Normal

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14
Q

Supplemental O2 is helpful in all causes of Hypoxemia except?

A

Right-to-left shunt

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15
Q

What form does iron carry O2?

A

Ferrous (Fe++)

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16
Q

O2 binding capacity of blood

A

20.1ml O2/100ml

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17
Q

O2 content of blood equation

A

O2 content = (O2 binding capacity x %Sat) + dissolved O2

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18
Q

Normally 1 g Hb can bind _____ ml O2

A

1.34

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19
Q

Cyanosis results when deoxygenated Hb _____

A

> 5g/100 ml

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20
Q

______ of arterial blood decreases as Hb falls, but _____ & _____ do not

A

O2 content;

O2 sat & arterial PO2

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21
Q

Arterial PO2 decreases w/ chronic lung dz b/c physiological shunt decreases _______

A

O2 extraction ratio

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22
Q

Causes defective O2 transport > low sat

A

methemoglobinemia

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23
Q

Causes of Methemoglobinemia?

A

Nitrites, benzocaine, metabolites of prilocaine

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24
Q

S/sx of cyanide poisoning

A

Tachycardia, hypotension, coma, acidosis, increased venous O2, rapid death

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25
Q

Tx of cyanide poisoning

A

sodium nitrite & amyl nitrites oxidize Hb to metHb which binds cyanide.
Thiosulfate binds this cyanide forming thiocynate which is excreted by kidneys

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26
Q

Cyanide blocks what enzyme that is needed for ATP?

A

Cytochrome oxidase

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27
Q

_________ is the driving force for the chemical reaction that creates oxyhemoglobin

A

O2 tension

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28
Q

P50

A

Indicates the partial pressure of oxygen required to achieve 50% of Hb saturation

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29
Q

Positive cooperativity

A

The sigmoid shape of oxygen-Hb curve that is a result of a change in affinity of Hb as each successive O2 molecule binds to a heme site

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30
Q

PO2 if Hgb sat is 100%

A

100 mmHg

31
Q

PO2 if Hgb sat is 75%

A

40 mmHg (mixed venous blood)

32
Q

PO2 if Hgb sat is 50%

A

25 mmHg

33
Q

Below a PO2 of ____ there will e a free fall of sat

A

60 mmHg

34
Q

Right shift causes:

A

Release of O2 from Hb

35
Q

Causes shift to the right of O2-Hb curve:

A
Increased CO2;
Increased Acidity (Bohr effect);
Increased DPG (diphophoglycerate a byproduct of glycolysis);
Increased Exercise;
Increased Temperature;
CADET
36
Q

Left shift causes:

A

Loading of O2 in Lungs

“Less O2 delivered”

37
Q

Normal value of P50

A

26-28 mmHg

38
Q

If P50 is increased there is a _____ shift. If P50 is decreased, there is a _____ shift

A

Right; Left

39
Q

Administration of 100% O2 is most effective in flat or steep portion?

A

Steep portion

40
Q

The shift of oxyHb curve in response to increase or decrease PCO2 is

A

Bohr effect

41
Q

Opioids shift the curve to the ____? Why?

A

Right; resp depression = more CO2

42
Q

At _______ CO2 diffuses into the blood that shifts the curve to the right > more release of O2

A

Tissue level

43
Q

At ______ CO2 diffuses from blood into alveoli that shift the curve to left > more loading of O2

A

Lungs

44
Q

What happens at 0.4 mmHg on the carbon monoxide-hgb dissociation curve?

A

No space would be left for oxygen

45
Q

The affinity of Hb for CO is _____ times higher than O2

A

250

46
Q

Functional anemia

A

Carboxyhemoglobin cannot carry O2

47
Q

What happens to PaO2 with carbon monoxide poisoning

A

It is normal/ no cyanosis. (PO2 is dissolved portion of O2)

48
Q

What happens to pulse ox during carbon monoxide poisoning?

A

It is normal b/c cannot differentiate

49
Q

CO at 1 Hb site increases O2 affinity of remaining 3 sites causing Hb to retain O2. This causes curve to shift?

A

To the left

50
Q

Tx for CO poisoning

A

100% O2 (will bump off CO from Hb)

51
Q

CO2 is produced in tissues & carried to the lungs in 3 forms:

A
  1. HCO3 (90% MAJOR FORM);
  2. Carbaminohemoglobin (Hb.CO2- small amt);
  3. Dissolved CO2 - small amt
52
Q

Equation to determine amt of CO2 dissolved in blood

A

PaCO2 x. 0.067

53
Q

IN lungs, oxygenation of Hb promotes dissociation of CO2 from Hb (therefore CO2 is released from RBCs)

A

Haldane effect

54
Q

______ chemoreceptors in carotid and aortic bodies mediate ____ of the CO2 response

A

Peripheral; 30%

55
Q

______ chemoreceptors in the medulla respond to H in brain ECF and mediate ___ of the CO2 response

A

Central; 70%

56
Q

Sensory information (PCO2, lung stretch, irritants, etc) is coordinated in _______ which sends signals to respiratory muscles

A

Brainstem

57
Q

Where is the medullary respiratory center located?

A

In reticular formation

58
Q

(Pacemaker);
Inspiration control;
Receives inputs via vagus (X) & glossopharyngeal (IX);
Output to diaphragm via phrenic nerve & external intercostals

A

Dorsal Respiratory Group

59
Q

Expiratory control;
Efferent via internal intercostal nerve;
Work only during exercise, when expiration becomes an active process

A

Ventral Respiratory Group

60
Q

Glossopharyngeal (IX) carries signals from _______ and vagus (X) from _______ and lung stretch receptors

A

Carotid bodies;

Arch of aorta

61
Q

Located in lower pons;

Stimulates inspiration, producing deep and prolonged inspiration gasp

A

Apneustic center

62
Q

Located in upper pons;
Inhibits respiration & therefore inspiratory volume and resp rate;
Adjust rate & depth of respiration

A

Pneumotaxic center

63
Q

Voluntary breathing;

Hypoventilation or hyperventilation

A

Cerebral cortex

64
Q

In the central chemoreceptors in the medulla ____ does NOT cross the BBB, but ____ does.

A

H+; CO2

65
Q

____ PCO2 and H+ stimulate breathing

A

Increased

66
Q

_____ PCO2 and H+ inhibit breathing

A

Decreased

67
Q

Why do acidosis & alkalosis not effect central chemoreceptors?

A

Bc acid ions cannot cross the BBB to go to the central receptor

68
Q

Peripheral chemoreceptors in the carotid and aortic bodies are stimulated by:

A

Decreased PO2;
Increased PCO2;
Decreased pH

69
Q

When these receptors are stimulated by dissension of the lungs, they produce a reflex decrease in breathing frequency

A

Hering-Breuer Reflex

70
Q

What is the resp drive of a normal healthy adult?

A

CO2 drive

71
Q

What is resp drive of a pt w/ 15yr hx of COPD?

A

Hypoxic drive (CO2 is blunted)

72
Q

Why is O2 administered w/ caution in COPD pts?

A

Too much O2 will drop hypoxic drive & they will stop breathing

73
Q

Right-to-left shunts always result in _______ bc of the admixture of venous blood w/ arterial blood

A

Decreased arterial PO2

74
Q

PO2 will be elevated on the right side of the heart with what type of shunt?

A

Left-to-right